function plot_fig(x_max,N,res1,res2,res3,res4)
h = x_max/N;
m = size(res1,1);
figure;
subplot(2,2,1)
plot(0:h:(m-1)*h,res1,'.-');xlim([0 2*pi]);ylim([-2 2.4]);title('(a) T = 0');
subplot(2,2,2)
plot(0:h:(m-1)*h,res2,'.-');xlim([0 2*pi]);ylim([-2 2.4]);title('(b) T = 1');
subplot(2,2,3)
plot(0:h:(m-1)*h,res3,'.-');xlim([0 2*pi]);ylim([-2 2.4]);title('(c) T = 2');
subplot(2,2,4)
plot(0:h:(m-1)*h,res4,'.-');xlim([0 2*pi]);ylim([-2 2.4]);title('(d) T = 4');